CVE-2025-69224 – CVE-2025-69224 is a request smuggling vulnerabi... (How to Fix)

📋 TL;DR

CVE-2025-69224 is a request smuggling vulnerability in AIOHTTP's Python HTTP parser that occurs when non-ASCII characters are present in requests. This affects systems using AIOHTTP versions 3.13.2 and below when running in pure Python mode (without C extensions or with AIOHTTP_NO_EXTENSIONS enabled). Attackers can exploit this to bypass security controls like firewalls or proxies by smuggling malicious requests.

💻 Affected Systems

Products:

aiohttp

Versions: 3.13.2 and below

Operating Systems: All

Default Config Vulnerable: ✅ No

Notes: Only vulnerable when using pure Python parser (without C extensions) or when AIOHTTP_NO_EXTENSIONS environment variable is set.

📦 What is this software?

Aiohttp by Aiohttp

View all CVEs affecting Aiohttp →

⚠️ Risk & Real-World Impact

🔴

Worst Case

Attackers bypass security controls to access internal systems, perform privilege escalation, or exfiltrate sensitive data through smuggled requests.

🟠

Likely Case

Bypass of web application firewalls or proxy protections to deliver malicious payloads to backend systems.

🟢

If Mitigated

Limited impact due to network segmentation, proper input validation, or use of unaffected configurations.

🌐 Internet-Facing: HIGH

🏢 Internal Only: MEDIUM

🎯 Exploit Status

Public PoC: ✅ No

Weaponized: UNKNOWN

Unauthenticated Exploit: ⚠️ Yes

Complexity: MEDIUM

Exploitation requires specific conditions (pure Python mode) and knowledge of request smuggling techniques.

🛠️ Fix & Mitigation

✅ Official Fix

Patch Version: 3.13.3

Vendor Advisory: https://github.com/aio-libs/aiohttp/security/advisories/GHSA-69f9-5gxw-wvc2

Restart Required: Yes

Instructions:

1. Update aiohttp using pip: pip install --upgrade aiohttp==3.13.3
2. Restart all services using aiohttp
3. Verify the update was successful

🔧 Temporary Workarounds

Enable C extensions

all

Ensure aiohttp is installed with C extensions (default behavior) to avoid vulnerable pure Python parser

pip uninstall aiohttp
pip install aiohttp

Disable AIOHTTP_NO_EXTENSIONS

linux

Remove or unset the AIOHTTP_NO_EXTENSIONS environment variable

unset AIOHTTP_NO_EXTENSIONS

🧯 If You Can't Patch

Implement strict HTTP request validation at proxy/WAF layer
Monitor for unusual request patterns containing non-ASCII characters

🔍 How to Verify

Check if Vulnerable:

Check if aiohttp version is ≤3.13.2 AND running in pure Python mode (check if C extensions are disabled)

Check Version:

python -c "import aiohttp; print(aiohttp.__version__)"

Verify Fix Applied:

Verify aiohttp version is 3.13.3 or higher and C extensions are enabled

📡 Detection & Monitoring

Log Indicators:

HTTP requests with non-ASCII characters in headers
Unusual request patterns bypassing normal validation

Network Indicators:

HTTP request smuggling attempts
Requests with malformed non-ASCII characters

SIEM Query:

search 'aiohttp' AND ('non-ASCII' OR 'request smuggling' OR 'CVE-2025-69224')

📊 Metadata

CVE ID: CVE-2025-69224

CVSS v3 Score: 6.5 (MEDIUM)

CVSS Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:N

CWE: CWE-444

EPSS Score: 0.04% exploit probability (12.4th percentile)

Published: January 5, 2026

Last Updated: January 14, 2026

🔗 References

https://github.com/aio-libs/aiohttp/commit/32677f2adfd907420c078dda6b79225c6f4ebce0 Patch
https://github.com/aio-libs/aiohttp/security/advisories/GHSA-69f9-5gxw-wvc2 Vendor Advisory,Patch

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🔗 Related Vulnerabilities

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